The present invention generally relates to billing or tariff calculation for communication systems. More particularly, the present invention relates to a method, device, and system for determining tariffs while conserving the processing resources of a central communication system processor.
It is frequently desirable for a person placing a call over a telecommunication system to be informed of the costs of the call. Thus, many telecommunication systems incorporate charging services which inform a calling party of the tariff. The tariff is typically based on some number of component charging elements, such as: 1) a charge indicator for indicating to a calling party whether that party will be charged for the call; 2) initial start units indicative of service charges to be assessed at the start of the charging period; 3) an initial time period indicative of the time from the start of the charging period until the first periodic increment of service charges; 4) a time period indicative of the time between subsequent increments of service charges; and 5) units per time period (UTP), indicative of the number of charging units (e.g., dollars) to be added periodically to service charges at the expiration of the initial time period and subsequent time periods. From this information, or similar parameters, the total tariff or charge for a call can be calculated.
FIG. 1 is a table showing exemplary tariff charging elements for different calling plans. In this example, subscribers to each plan are assessed a monthly charge (in this example, 7300 yen or 4400 yen), and are also charged for calls according to the rates for various tariff classes (TC=a-f) as expressed in the table. The tariff classes are determined based upon the distance involved in a subscriber""s call (e.g., whether the call is within a predetermined local area, some other area within 160 km, or an area greater than 160 km), and upon the particular monthly plan in which the subscriber is enrolled. For each tariff class, the tariff to be applied depends upon the time frame during which the call takes place (e.g., day, night, morning).
FIG. 2A is a graphical representation of how the charging elements affect the service charges. The graph shows the applicable service charges (including an initial unit IV and additional units per time period UTP) as a function of time, i.e., the service charges that would be applied if a call xe2x80x9creleasexe2x80x9d were to occur at a particular time, in this case designated by X.
Tariff charging elements are subject to change due to factors such as a change in day (e.g., from a mid-week day to a weekend day or holiday), or a change in the time of day (e.g., from a daytime rate to an evening rate). Sometimes, a tariff switch will occur during a call. FIG. 2B is a graphical representation showing the effect of such a tariff switch at time X. A typical tariff change can be expressed as a change in charge rate per time period (e.g., from $0.10/minute to $0.20/minute), a change in time period duration (e.g., $0.10/minute to $0.10/30 seconds), or both.
Most charging services are implemented by a central system processor, which, in the event of a change in the tariff information during a communication, must re-determine the tariff charging elements for each caller and notify each calling party of the change. Thus, when a tariff change occurs, significant signal processing resources are consumed. Further, because a tariff change may affect a large number of callers, there can be a significant drain on central system processor resources when a tariff change occurs, and there can also be significant delays in notifying calling parties about the tariff change. Known tariff calculation methods and systems do not adequately address this problem.
U.S. Pat. No. 5,303,297 to Hillis discloses a billing system which adapts to a communication system in real time. A central system processor, or billing computer, computes the rate, which is indicated to an individual user. If the user agrees to the rate, the call is connected and the central system processor recalculates the rate based on the overall system load. Each time the rate changes (due to system load changes), the user is notified and asked for approval.
U.S. Pat. No. 5,488,655 to Hamlen discloses a method and system for controlling traffic load by using variable price incentives. Hamlen is similar to Hillis in that a rate is calculated by a central processor, which provides the rate to the user.
U.S. Pat. No. 4,751,728 to Treat discloses a telephone call monitoring, metering and selection device which attaches to a standard telephone. A user pre-programs rate information for multiple telephone service providers (e.g., different long distance companies), which allows the device to determine which service provider will cost the least for a given call. While the device is capable of calculating rates and displaying cost to a user, the device is not an integral part of the telephone. Further, since the rate information is programmed by the user, the device is subject to human error.
U.S. Pat. No. 5,400,395 to Berenato discloses a telephone line selector and accounting system for selecting the lowest-priced long distance carrier and displaying rate information to a user during a phone call. The system automatically calculates rate information based on carrier update tones, and can be connected between several carriers and multiple telephones. The device therefore is not an integral part of the telephone.
All of the above-described systems involve the calculation of rates at a device external to a telephone device, and therefore do not adequately address the problem of reducing processor load upon the occurrence of a tariff switch. It would be desirable for a rate calculation system to reduce this processor load.
The present invention overcomes the above-noted problems, and achieves additional advantages, by providing for a tariff calculation system in which tariff information is provided to a communication system user (i.e., a mobile communication device) at call set-up. By providing the tariff information to a device at call set-up, the user""s communication device can perform the tariff calculation, thus reducing the processor load of the central system processor.